Who Knew Cutting Circles was So Easy

I am helping my 8th grade son build a wind turbine for his Science Fair Project. He is testing the impacts of different blade designs on energy production efficiency. As part of the project, we have to build a hub to attach the blades to the generator unit.

So I thought about different ways to cut a circle – not sure yet how big we need, but probably a half foot to foot in diameter will be needed. The options were – router, drill press (most likely not enough capacity), table saw or bandsaw. As I want my son to build most of this project as possible, I decided on the Bandsaw. About 5 minutes worth of putting together a jig and that was it. Once we know how big a hub we need, I will help him cut out the three circles he will need.

I was amazed at how well it worked. Started playing around with it and made multiple test circles for fun…Remember, I am new to this hobby.

Will post pictures of the Wind Turbine when it is complete…

As an aside, his theory is if he builds a blade with an airfoil design known to provide a lot of lift (vs traditional air foil designs) that it will improve the efficiency of the turbine. He will be testing a flat blade, a traditional symmetrical airfoil and a KF-3 (Kline-Fogelman) airfoil design…It will be interesting to see the results.

I will keep you posted as we progress and show a few pictures of the turbine (even though not exactly fine woodworking….

I have attached a few pics of the jig. I just used a scrap piece of plywood and a short runner for the miter slot on the saw. I just finished making runners for a small cross-cutting sled so I had no work to do as I had a few extra pieces to use for the runner…

Here is the jig:

I used a spring clamp as a stop to keep the jig in the right position on the saw:

I drew a line on the jig at the end of the kerf and drilled holes at 1” increments. I clipped the head off of a small nail to use as rotation point for the work piece. Here is a circle with a 1” radius:

As you can see, it is a very quick and dirty effort, but will do what we need for now.